Obviously not in the same way. Overall system failure rates comparing cable vs digital throttle control - I have no idea.

I do know that I can’t remember the last time I drove a car with a bad idle, which is much more than anyone who lived in 80s can say.

Also: throttle by wire permits simpler cruise control integrations, better fuel economy and also facilitates the operation of safety systems like traction/stability control - so it’s not exactly a like-for-like comparison.

This is a nit, but idle control was automated well before drive-by-wire took over. Idle could be on closed loop control, but if the idle solenoid failed, it was less catastrophic than losing throttle control.

Heh, I think 50% of my experience working on 90s cars was cleaning IACVs

Throttles linkages are a regular maintenance item on vehicles with mechanical throttle linkages. And all (non-antique) engines with mechanical throttle linkages have return springs as a safety backup for when/if they do fail. Some of them also have redundant linkages on top of this. It is not uncommon for throttle cables to have their maintenance neglected, and eventually, they will wear out and break.

Throttle's did fail before drive by wire but I have no data to compare.